The invention relates to an improvement in the construction of an electrophotographic copying machine with a cleaning unit for a photosensitive surface thereof.
An electrophotographic copying machine includes a photosensitive member, on the surface of which an electrostatic latent image corresponding to an original to be copied is formed and subsequently converted into a visual image by the use of a developing solution containing a toner. The visual image is transferred onto a record sheet to provide a copy. In the process described, after the transfer step has been conducted to transfer the visual image onto the record sheet, there remains a certain amount of toner on the photosensitive surface, which must be removed before commencing the next copying cycle. To this end, a variety of cleaning units are known, which include blades formed of a resilient material, such as synthetic resin, and having an edge, or a cleaning member, such as a sponge roller held in abutment against the photosensitive member and supplied with a cleaning liquid, such as a toner-containing liquid, to remove any residual toner. A recent trend toward an increase in the speed of a copying operation has made it difficult to remove a residual toner completely with a single cleaning member, so that copying machines having an operation cycle of a reduced duration, or adapted to operate with an increased supply of toner, are provided with a plurality of cleaning members which are disposed along the direction of movement of the photosensitive member in an attempt to provide a complete removal of any residual toner.
However, conventional cleaning units including a plurality of cleaning members have been constructed as a mere juxtaposition of independent cleaning members, which requires a troublesome dismounting operation when the photosensitive member is disassembled for the purpose of replacement, inspection, or adjustment, or in the event of occurrence of a paper jamming. Sometimes the photosensitive surface of the member may be damaged by one of the cleaning members which has been inadvertently left in position. Additionally, when the individual cleaning members are mounted in place again, they must be individually adjusted so as to provide an adequate contact pressure with respect to the photosensitive member. As the number of the cleaning members increases, some of them may be left without adjustment.